Propeller



1. S. FUNK.

PROPELLER.

APPLICATION FILED DEC. 10, 1920.

1 ,396,680. Patented Nov. 8, 1921.

2 SHEETSSHEET I.

I. S. FUNK.

PROPELLER.

APPLICATION FILED DEC. 10. 1920.

1,396,680. Patented Nov. 8, 1921.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

JACQUES S. FUNK, OF BALTTMORE, MARYLAND, ASSIGNOR F ONE-HALF TO RICHARDW. COOK.

PROPELLER.

To all whom it may concern Be it known that I, JAo Uns S. FUNK,

a citizen of the United States, and a resication. i i

Mv invention. relates to propellers for aircraft, although it is notrestricted to such use. i

In propellers now in use there is what is known as slip or lostresistance at the hub which places the propeller, at this :point, underconsiderable strain. 1

The primary purpose of the present invention is to overcome thisdifficulty and to that end the inner ends of the propeller blades areprojected past the axis or propeller shaft upon opposite sides thereof.

A further object of the invention is to provide a metal airplanepropeller, and which is. ;to a certain degree. flexible.

It is also another object of the invention to provide a propeller foraircraft including a plurality of laminations or sheets locked togetherin a novel manner.

\Vith the preceding and other objects and ad antages in mind, theinvention consists in the novel combination of elements, constructionand arrangement of, parts to be hereinafter more fully described.claimed and illustrated in the accompanying drawings, wherein Figure 1is a side elevation of an airplane propeller constructed in accordancewith my invention;

Fig. 2 is a similar view taken at right angles to Fig. 1;

Fig. 3 is a side elevation of one of the units embodied in theinvention;

Fig. i is a horizontal sectional view taken on line -1-4 of Fig. 2;

Fig. is a side elevation of a modified tyie of the invention; and

ig. 6 is a like view taken at right angles to Fig. 5; and

Fig. 7 is an elevation of one of the units embodied in the modifiedconstruction.

Referring in detail to the drawings, particularly to Figs. 1 to 4:inclusive. the numerals 5 and 6 designate a pair of sheet metal units orsections which constitute the propeller. It will be stated that anydesired number of these sections may be employed Specification ofLetters Patent.

Patented Nov. 8,1921.

Application filed December 10, 1920. Serial No. 429,751.

in constructingtlie propeller, and as these units are identical, onlyone of them will be specifically described.

As shown in Fig. 4, each unit or section comprises a. longitudinal sheetof relatively flexible metal designated by the numeral. 7. This sheet ofmetal is shaped in the same manner as the usual airplane propeller andthe blades 8 thereof are set at a pitch of 45 or any other pitch thatmaybe found practical. The unit or section 7 is formed with incisions 9at its longitudinal edges at points which are equidistant from the axisor shaft receiving opening 10, and the longitudinal edges of the blades8 extended in divergent relation in proximity to the axis or shaftopening 10. Thus when the units are assembled as is shown in Fig. 2, thedivergent parts in proximity to the hub' or shaft and designated by thenumeral 11, constitute air gripping pockets.

Each of the sections 7 is formed with inwardly extending slots 12 at itsopposite longitudinal edgesand at points equidistant from the incisions9, and also provided with openings 13 at the inner ends of the slots.

In assembling the units, the latter are arranged in crossed relationwith the slots in the blades facing each other and then shiftedtransversely to cause the slots to interlock. This, as is shown in Fig.1, disposes the blades of each unit in overlapping.relation.

The units are then fixed or sccured'together by screws or otherfasteniiigs 1-1 passing through the openings 13. Passing through theaxis of the propeller is a threaded stem 15 adapted to be connected withthe usual airplane propeller. as shown, and threaded on this stem 15 andupon opposite sides of the propeller are nuts 16 which positively lockthe propeller to the stem 1:).

In the modification illustrated in Figs. 5 to Tinclusive, a disk 16 isemployed and a pair of propeller sections or units 17 and 18 arearranged upon the opposite faces of this disk and passing through thesesections and disk is a mounting designated at 19. Each of these sections17 and 18 is formed with extensions 20 which are secured to the disk 16by fastenings 21. The blades of each section. like the structure abovedescribed, are provided with slots 22 adapted for interlockingengagement when the impeller is to be used as a, two'bladed prope ler.How

-my invention herein ever, with this embodiment of the invention, it ismost desirable to use the same as a four-bladed device. I

It is to be understood that the forms of shown and described are to betaken as preferred examples of the same, and that various changes in theshape, size and arrangement of parts may be resorted to withoutdeparting from the spirit of the invention or the scope of the subjoinedclaims.

Having thus described my invention, what I claim as new and desire tosecure and protect by Letters Patent of the United States, is: i

1. A propeller comprising a plurality of units each of which consistingof a flexible sheet having oppositely and angularly disposed blades atits ends, the units beingprovided with transverse slots at theirlongitudinal edges which receive the blades whereby to dispose the unitsin superposed relation.

2. A propeller comprising a plurality of units each of which consistingof a flexible sheet having oppositely and angularly disposed blades atits ends, the units being proided with transverse slots at theirlongitudinal edges which receive the blades whereby to dispose the unitsin superposed relation, the units being also provided with incisionsupon opposite sides of its axis and at their longitudinal edges wherebyto afford divergent air gripping members which extend entirely acrossthe axis of the propeller.

3. An airplane propeller comprising a plurality of units each beingformed from a sheet of relatively flexible material, and each includingoppositely inclined blades, each of the units being provided withincisions at their longitudinal edges and upon opposite sides of thepropeller axis, each ot'the units being also provided with slots whichhave interlocking engagement with each other to retain the unitstogether and to dispose the blades in overlapping relation, andfastenings also passing through the units.

4. An airplane propeller comprising metal sections, each of which beingshaped substantially like an airplane propeller, means for retaining thesections locked together, and divergent parts formed with the sectionsadjacent the propeller axis adapted to grip the air at that point andthereby eliminate slip at the axis.

5. An airplane propeller comprising a disk, a plurality of bladescarried thereby, each of which having an angularly disposed part whichoverlies the disk and constituting air gripping members.

6. An airplane propeller comprising a central member for connection withthe drive shaft of an airplane, a plurality of radially disposed bladescarried thereby, the inner end of each blade being set at an obliqueangle with respect to the central member and overlying the latter andconstituting air gripping members.

7. An airplane propeller comprisinga central member for connection withthe drive shaft of an airplane, a plurality of radially disposed bladescarried thereby, the inner end of each blade being set at an angle withrespect to the central member and overlying the latter, the blades beingcapable of being moved into superposed relation when it is desired touse the propeller as a double bladed structure.

JACQUES b. FUNK.

